A bit less random than most of the vs. threads here, I think.
Kishimoto Seishi's creation, 666 SATAN vs. Kishimoto Masashi's creation, NARUTO.
As if you couldn't tell already, both of these manga authors are related. They are both brothers, Seishi being the younger brother and Masashi being the older brother.
I wanted to see which brother has the better creation. XP
For me, I'll go with 666 Satan.
-no filler hell. (no anime, so no fillers, YAY!)
-Jio is 100000000x more hot than Naruto. (Timeskip Jio... *drool*)
-Story in 666 Satan doesn't become worse in Timeskip like Naruto's does.
-Jio is a lot more interesting of a character than Naruto and less generic (I mean, he's possessed by Satan yet he's also the main hero...)
-Characters in 666 Satan are also much more interesting than Naruto characters, as all of them actually have backgrounds, WHOAMG! 8O
The only thing I'd say Naruto beats 666 Satan at is the artwork in the earlier chapters. 666 Satan has fugly artwork in the first few volumes, but it gets much better (and chances are, it probably isn't done on the computer! :O ).
There's also the fact that the beginning to 666 Satan is very 'meh' compared to the beginning of Naruto, but it gets better while Naruto gets worse.